A device for feeding a pressurized medium or liquid from a stationary housing to a rotatable structural component cooperating with it generally comprises a valve ring having a running surface formed thereon. This valve ring is provided as a part of or affixed to the rotatable component and has a plurality of valve passages opening onto the running surface, in each of which a nonreturn valve or checkvalve is mounted.
The stationary housing has a shoe communicator with at least one of the nonreturn valves with its sealing surface riding on the running surface of the valve ring, extends only over a portion of the periphery of the valve ring, and is provided in its sliding shoe supported slidably in the housing with an inlet for the pressurized medium and a chamber or compartment for the compressible medium.
A coupler device of this type is described in German Pat. No. DE-PS 24 03 280. Such an apparatus with a hydrostatically discharging sliding shoe is used in hydrostatic devices such as piston pumps and rotary transmission mechanisms for reducing the friction between parts moving relative to each other.
In order to guarantee a secure contact between those parts, this unit basically overcompensates. This means, that, for example, the force applied by a piston on the slidable sliding shoe is chosen to be somewhat greater than the hydraulic separating force occuring between the moving parts. The device, which assumes a definite pressure development in the gap separating the movable parts for an approximately constant balance, operates with no problems at approximately constant rotational speeds and with fluids having a high viscosity (n&gt;20 cSt).
Difficulties, that is, strong deviations from the desired balance, occur particularly with low viscosity media (n&lt;20 cSt) and with different operating conditions, for example, large rotational speed changes of the movable component parts and, particularly, when movable components are accelerated from a stop to their nominal rotational speed in the presence of the input pressurized medium.